A power ratchet wrench is widely applied in the field of fastening operations, and particularly a through-hole type power ratchet wrench is adapted for some narrow operating environments as having a smaller operating head. Generally, a rotation direction of a ratchet socket at a head portion of the ratchet wrench may be changed by manually reversing the ratchet wrench. However, it is very difficult for an operator to reverse the ratchet wrench in some especially narrow operation environments. The operator needs to draw the ratchet wrench out of the operating environment first, reverse it, and then replace it into the operation environment again. Obviously, this will adversely affect the operation efficiency of the operator.